ABSTRACT Multiple stigmas related to sexuality, race, and HIV infection negatively impact HIV testing, engagement in HIV care, and consistent viral suppression (VS) among young Black or Latino men who have sex with men and transgender women (YBLMT). At present, few interventions have addressed the effects of intersectional stigma among HIV-infected and uninfected populations. In response to RFA-MH-18-606, this study tests whether an online intervention tailored for intersectional stigma amelioration can elicit online social support, promote intervention engagement, and mitigate the impact of multiple stigmas on HIV-related outcomes. We will recruit and enroll 1,050 young (ages 15-29), racially and ethnically diverse men who have sex with men and transgender women affected by HIV across the United States. Using a HIV-status stratified randomized trial design, participants will be assigned into one of three conditions (information-only control, a researcher-driven social network intervention, or a peer-driven social network intervention). Behavioral assessments will occur at baseline, 3, 6, 9 and 12 months; biomarkers (viral load) are scheduled for baseline, 6 and 12 months. The primary outcome is stratified by HIV status and defined as successful engagement in care (consistent VS for HIV-positive participants and routine testing for HIV-negative participants). The specific aims are: 1) Test whether an online intervention that promotes user-generated content and engagement to address intersectional stigma is associated with improvements in the HIV prevention and care continuum (HIV testing, antiretroviral adherence, VS) as compared to an information-only control arm; 2) Explore whether user engagement, as measured by quantitative and qualitative paradata, mediates the intervention?s stigma- and HIV care-related outcomes; and, 3) Examine how changes in intersectional stigma and improvements across the HIV care continuum vary between the researcher-driven vs. peer-driven social network intervention conditions. Our research study is innovative given its focus on intersectional stigma as a key target of intervention, and its ability to assess how different kinds of online social network structures influence participants? engagement over time, reduce experiences of intersectional stigma, and improve successful engagement in care. This research addresses a critical need to reduce the effects of multiple stigmas in a priority population using an intervention delivered through a highly appealing, widely-utilized technology. If effective, this form of stigma amelioration via online support can be broadly disseminated to reduce HIV transmission and improve care among YBLMT.